chore: Add Timezone and restart policy for postgres backup docker

[mateuscomh]

This PR makes two improvements to the docker-compose.yml file used for PostgreSQL backups inside doc page self-hosted docker:

• Restart policy backup postgres docker-compose
  Adds a restart policy to the backup service to improve resiliency and ensure that the service recovers automatically in case of failures. Without this explicit configuration, the backup works only once and ends, without this explicit configuration, the backup only works once and ends

• Add Timezone on docker-compose postgres backup
  Adds the TZ environment variable with the value Europe/London (example) to ensure that the container uses the correct time zone. Showing the user the possibility of changing the TZ and daily backups taking place at 00:00 in their time zone

[mateuscomh]

After using and testing, i have add new options on docker-compose to backup the postgress BD

• Define explicit image version in docker-compose
• Add healthcheck to monitor container health on port 8888